Enlargement or Asymmetry of the Lateral Ventricles Simulating Hydrocephalus

Abstract

The lateral ventricles have a wide range of appearances that can be considered normal. There may be variations in size between sides or between different regions (e.g., the bodies may be larger than the temporal horns, or vice versa). Such asymmetry occurs in about 5–20 % of the population, depending on what is considered asymmetry and which portions of the ventricle are compared to the opposite side. More commonly, for unknown reasons the right lateral ventricle is larger than the left by about a 3:1 ratio. This may be seen at any age, from the fetus to the elderly population. Such asymmetry should be considered normal as long as the ventricular size and configuration do not fit the criteria for hydrocephalus. Additionally, varying degrees of cerebral atrophy (and particularly adjacent white matter atrophy surrounding the lateral ventricles) can accentuate this appearance and mistakenly lead to the diagnosis of hydrocephalus, leading to unnecessary shunting.